Abstract: A novel process for the polymerization of aziridine compounds is disclosed. The polymerization process includes mixing an aziridine compound with a polymerization initiator having the formula: ##STR1## where R.sup.1 is an alkyl radical of 1 to 18 C atoms,R.sup.2 is an alkyl radical of 1 to 18 C atoms or a phenyl alkyl radical of 7 to 18 C atoms, wherein said alkyl radicals may contain an ester group and/or ether group, R.sup.3 and R.sup.4 are hydrogen, an alkyl radical of 1 to 18 C atoms, and/or an aryl radical which can be substituted with a chloro, nitro or alkoxy group, whereby the alkyl radicals of R.sup.3 and R.sup.4 together or in combination with B can form a cycloaliphatic or heterocyclic ring, B is an electron attracting radical, and A.sup..crclbar. is a non-nucleophilic anion.Polyimines are quickly formed at ambient temperature.